The strain upon the divisions during this continuous fighting had been so great that it was found necessary to give them all the rest and relief possible. With this object in view, the Sixth Corps front was held now by only two divisions, the Fifty-sixth upon the right and the Twenty-ninth on the left. In order to cover the whole line, the Corps mounted troops were advanced and were placed in the trenches upon the south of the Scarpe, which were less vulnerable since the capture of Rœux by the Fourth Division.
May 16
In the dim light of the very early morning of May 16, after a heavy shell-fall, a new division of the enemy was thrust forward just north of the Scarpe. In a long day's fighting it was practically destroyed, for though in its first ardent advance it flowed over the shot-shattered advance posts, it was finally held, and then after a long tussle was shot out of its new positions by the rifles and Lewis guns, until before evening it was back whence it started. In this brisk action thousands of the assailants were killed or wounded with nothing to show for it save the substantial losses which they inflicted. This very severe attack fell mainly upon the Fifty-first Division, who showed once more that British formations, even if penetrated, are very far from being defeated.
On May 18 there was a spirited local operation by the 8th Middlesex of the 167th Brigade, in which they made a very gallant bombing attack upon that portion of Tool Trench which was not yet in British hands. The opposition, however, was so strong that no permanent good could be effected. On the next day there was a further attempt to get forward, both by the 167th and by its neighbour, the 87th Brigade. The fire was too deadly, however, and the advance was not successful. This failure seems to have been due to a knowledge on the part of the enemy as to the coming assault, for the machine-gun fire and the barrage opened in full force at the very moment when the leading line of infantry sprang over the lips of their assembly trenches.
May 20
May 20 marked a successful advance of the Thirty-third Division on the right of the Seventh Corps, against the Hindenburg Line in the Sensée Valley and southwards towards Bullecourt. On this occasion there was no preliminary bombardment and no creeping barrage. A mist helped the 98th Brigade to deploy unobserved under the bulge of the chalk hills that rise to the south of the Sensée Valley. When this mist rose the Germans had a fine, though transitory, view of British tactics, for the battalions were advancing as upon an Aldershot field day. The 100th Brigade worked down the Hindenburg Line north of the river, crossed it, and joined hands with their comrades on the south. It was a complete surprise, and counter-attack was checked by the volume of the British gun-fire which tore up the whole rear of the German defences. The result was the capture of more than a mile of the front line on either side of the Sensée River, with half a mile of the support line, and 170 prisoners, with many machine-guns. The losses in this well-managed affair were well under a thousand.
May 30
For ten days after this the southern front was quiet, and the only change consisted in the withdrawal of the Fifty-sixth and the substitution of the Thirty-seventh Division. On May 30 a minor operation was carried out upon a small section of German trench by the 88th Brigade, assisted by the 8th East Lancashires from the 112th Brigade. This attack had some partial success, but was eventually driven out of the captured by a strong counter-attack, with the result that a small body of the 3rd Middlesex Regiment, some thirty in number, were isolated and taken or slain. Greater success, however, attended the next operation, which was an attack upon June 14 upon Infantry Hill, which included Hook Trench and Long Trench. This very successful advance was carried out by the 1st Gordons and 2nd Suffolks, the two regular battalions of the 76th Brigade. The whole position was stormed by a surprise attack and 180 prisoners were taken. A counter-attack was broken up by the British artillery. The losses of the storming battalions were well under 400 men. Two days later the Germans again made a strong effort to thrust back the British advance, but again they failed with considerable loss, save at the more advanced posts which they occupied. A British attempt next morning to regain these lost posts was not successful. Upon June 18, the anniversary of the great day when Germany and Britain fought together for freedom, there was a fresh attack to retake Hook and Long Trench. It surged up to and into the trenches, but could not disperse the sturdy men of Suffolk, who held them. The German wave lost its momentum and broke up into pools, which soon were swept back with the ebbing tide. Nearly 200 prisoners were taken in this spirited affair.
June 5